Differential methylation of novel gDMRs in uniparental tissues of germline origin. Fragment sizes (kb) are indicated to the right. (A) Sperm (SP), ovarian teratoma (OT), or complete hydatidiform mole (CHM) was digested, and Southern blot hybridization was performed with the gDMRs indicated, as described in the legend to Figure 2. Multiple OT and CHM were examined with similar results, although only one is shown. (B) Similar experiments were performed with an unmethylated CpG island in the retinoblastoma gene (RB), with a CpG island upstream of H19 that shows preferential methylation of the paternal allele, and with a CpG island within the SNRPN gene that shows preferential methylation of the maternal allele.